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PubMed2004

Analysis of mutagenic activity of airborne particulate matter, standard reference materials and reference compounds using base pair-specific Salmonella typhimurium tester strains.

The mutagenicity profiles of organic extracts of airborne dust samples from Mannheim, Germany, and two standard reference materials (SRM) as well as eight compounds with different chemical properties were investigated using tester strains Salmonella typhimurium TA700x (Ames II Assay). Each strain of this series carries a unique missense mutation in the histidine operon and is reverted by only one specific base substitution out of six possible changes. Mutation patterns of eight compounds with different modes of genotoxic action reveal significant differences. Samples of airborne particulate matter (APM) from an industrialized town in Germany (Mannheim) were collected for five consecutive days once a month for 1 year using an automatic high-volume air sampler. Samples taken from Monday to Friday were Soxhlet-extracted and prepared according to standard methods. Although the threshold limit for the least active strains is not triggered by all samples, it can be concluded that mutation patterns of the samples do not vary between different seasons. Standard reference materials (SRMs) were prepared and tested using the same methods. SRMs and APM samples from Mannheim reveal similar mutagenicity profiles in TA700x strains. The comparison of the mutagenicity profiles of air dust extracts from Mannheim and the SRMs, respectively, with reference compounds investigated so far shows some similarities although the patterns do not fit perfectly. Mutagenicity profiles of TA700x-activity of nitro-aromatic compounds published so far are similar to those of APM collected in Mannheim, Germany, as well as to standard reference materials 1648 and 1649.

Air Pollutants↗
PubMed2006

Integrated assessment modeling of atmospheric pollutants in the Southern Appalachian Mountains: Part II. Fine particulate matter and visibility.

As part of the Southern Appalachian Mountains Initiative, a comprehensive air quality modeling system was developed to evaluate potential emission control strategies to reduce atmospheric pollutant levels at the Class I areas located in the Southern Appalachian Mountains. Six multiday episodes between 1991 and 1995 were simulated, and the skill of the modeling system was evaluated. Two papers comprise various parts of this study. Part I details the ozone model performance and the methodology that was used to scale discrete episodic pollutant levels to seasonal and annual averages. This paper (part II) addresses issues involved with modeling particulate matter (PM) and its relationship to visibility. For most of the episodes, the fractional error was approximately 50% or less for the major constituents of the fine PM (i.e., sulfate [SO4] and organics) in the region. The mean normalized errors and fractional errors are generally larger for the NO3 and soil components, but these components are relatively small. Variations in modeling bias with pollutant levels were also examined. The model showed a systematic overestimation for low levels and an underestimation for high levels for most PM species. For ammonium, the model showed better performance at lower SO4 concentrations when the measured SO4 was assumed to be completely neutralized (ammonium sulfate) and better performance at higher SO4 concentrations when the partially neutralized (ammonium bisulfate) assumption was made. The contributions of various components of PM to reductions in visibility were also calculated; SO4 was found to be the major contributor.

Air Pollutants↗
PubMed2000

Polycyclic aromatic hydrocarbon levels and mutagenicity of inhalable particulate matter in Santiago, Chile.

The air in Santiago, Chile, is among the most highly polluted in the world. Due to the high levels of pollutants and the high incidence of respiratory diseases, especially in the most susceptible groups, Santiago has been declared a saturated zone for PM(10), O(3), and CO. The aim of this work was to investigate polycyclic aromatic hydrocarbon levels and mutagenic activity of Santiago s fine and coarse fractions of inhalable particles. The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by high-performance liquid chromatography in organic extracts from respirable particles (OERP). Respirable particulate matter (fine and coarse) contains high levels of PAHs including six mutagenic ones classified by the IARC as carcinogenic, which represented at least 45% of the total PAH concentration. A seasonal effect was observed, with higher values in months with lower temperatures. Although a significant decline of PAH levels in OERP was observed in the last years, the levels of carcinogenic PAHs are still higher than those reported in cities of the United States, Australia, and Europe. OERP were highly mutagenic and contained direct and indirect mutagens, which produced both frameshift and base substitution mutations in Salmonella typhimurium. In addition, organic extracts from total suspended particles were also highly mutagenic at the tk locus in h1A1v2 human lymphoblasts in culture. In spite of the important decrease in PAHs in the period 1991-1996, direct mutagenic response has not changed significantly, suggesting that the levels of direct mutagenic pollutants (e.g., nitroarenes) have not decreased considerably during the last years. These results suggest a risk for Santiago s inhabitants since pollutants adsorbed in inhalable particles are highly mutagenic and can damage DNA.

Administration, Inhalation↗
PubMed2003

Exposure to particulate matter, volatile organic compounds, and other air pollutants inside patrol cars.

People driving in a vehicle might receive an enhanced dose of mobile source pollutants that are considered a potential risk for cardiovascular diseases. The exposure to components of air pollution in highway patrol vehicles, at an ambient, and a roadside location was determined during 25 work shifts (3 p.m. to midnight) in the autumn of 2001, each day with two cars. A global positioning system and a diary provided location and activity information. Average pollutant levels inside the cars were low compared to ambient air quality standards: carbon monoxide 2.7 ppm, nitrogen dioxide 41.7 microg/m3, ozone 11.7 ppb, particulate matter smaller 2.5 microm (PM2.5) 24 microg/m3. Volatile organic compounds inside the cars were in the ppb-range and showed the fingerprint of gasoline. PM2.5 was 24% lower than ambient and roadside levels, probably due to depositions associated with the recirculating air conditioning. Levels of carbon monoxide, aldehydes, hydrocarbons, and some metals (Al, Ca, Ti, V, Cr, Mn, Fe, Cu, and Sr) were highest in the cars, and roadside levels were higher than ambient levels. Elevated pollutant levels were related to locations with high traffic volumes. Our results point to combustion engine emissions from other vehicles as important sources of air pollutants inside the car.

Air Pollutants↗
PubMed1977

Effects of agitation on size distribution of particulate matter in large-volume parenterals.

The particle-size distributions of six types of large-volume parenterals subjected to different degrees of agitation were determined using an automatic particle counter. Data acquired from each solution, which had been maintained in a stored condition, subjected to agitation by inverting 20 times, and then mechanically shaken for 30 min, produced a linear relationship between log N greater than D and log D. Both the slope (K) and the number of particles per milliliter exceeding 1 micrometer in diameter (N greater than 1) exhibited a dependence on the degree of agitation. Their combined effect indicates that agitation by 20 hand inversions removed particulate matter from the surface of the container, which increased the total number of particles in solution (greater than 1 micrometer) but did not significantly alter the relative size distribution. Agitation for 30 min, however, disintegrated agglomerates and produced a particle-size distribution with a greatly increased number of particles whose diameters were less than 1 micrometer and a corresponding decrease in the number of particles exceeding 1 micrometer in diameter. The particle-size distribution of a parenteral solution determined by this in situ instrumental method was, therefore, dependent upon the degree of agitation to which the parenteral was subjected prior to examination.

Chemistry, Pharmaceutical↗
PubMedDate not supplied

Particulate matter and heart rate variability among elderly retirees: the Baltimore 1998 PM study.

This study investigates the relationship between ambient fine particle pollution and impaired cardiac autonomic control in the elderly. Heart rate variability (HRV) among 56 elderly (mean age 82) nonsmoking residents of a retirement center in Baltimore County, Maryland, was monitored for 4 weeks, from July 27 through August 22, 1998. The weather was seasonally mild (63-84 degrees F mean daily temperature) with low to moderate levels of fine particles (PM2.5 < 50 micrograms/m3). Two groups of approximately 30 subjects were examined on alternate days. A spline mixed-effects model revealed a negative relationship between outdoor 24-h average fine particulate matter (PM2.5) and high-frequency (HF) HRV that was consistent with our earlier Baltimore study for all but 2 days. These 2 days were the only days with significant precipitation in combination with elevated PM2.5. They were also unusual in that back-trajectory of their air masses was distinctly different from those on the other study days, emanating from the direction of rural Pennsylvania. Mixed-effects analysis for all 24 study days showed a small negative association of outdoor PM2.5 with HF HRV (-0.03 change in log[HF HRV] for a 10 micrograms/m3 increment in PM2.5) after adjustment for age, sex, cardiovascular status, trend, maximum temperature, average dew point temperature, random subject intercepts, and autocorrelated residuals. After excluding study days 4 and 5, this association was strengthened (-0.07 change in log[HF HRV] for 10 micrograms/m3 PM2.5, 95% CI -0.13 to -0.02) and was similar to that obtained in an earlier study (-0.12 change in log[HF HRV] for a 10 micrograms/m3 increment in outdoor PM2.5, 95% CI -0.24 to -0.00) [Liao D., Cai J., Rosamond W.D., Barnes R.W., Hutchinson R.G., Whitsel E.A., Rautaharju P., and Heiss G. Cardiac autonomic function and incident coronary heart disease: a population-based case-cohort study. The ARIC Study. Atherosclerosis Risk in Communities Study. Am J Epidemiol 1997: 145 (8): 696-706]. Acute (1 to 4 h) previous PM2.5 exposure did not have a stronger impact than the 24-h measure. A distributed lag model incorporating the six preceding 4-h means also did not indicate any effect greater than that observed in the 24-h measure. This study is consistent with earlier findings that exposures to PM2.5 are associated with decreased HRV in the elderly.

Aged↗
PubMed2006

Wintertime vertical variations in particulate matter (PM) and precursor concentrations in the San Joaquin Valley during the California Regional Coarse PM/Fine PM Air Quality Study.

Air quality monitoring was conducted at a rural site with a tower in the middle of California's San Joaquin Valley (SJV) and at elevated sites in the foothills and mountains surrounding the SJV for the California Regional PM10/ PM2.5 Air Quality Study. Measurements at the surface and n a tower at 90 m were collected in Angiola, CA, from December 2000 through February 2001 and included hourly black carbon (BC), particle counts from optical particle counters, nitric oxide, ozone, temperature, relative humidity, wind speed, and direction. Boundary site measurements were made primarily using 24-hr integrated particulate matter (PM) samples. These measurements were used to understand the vertical variations of PM and PM precursors, the effect of stratification in the winter on concentrations and chemistry aloft and at the surface, and the impact of aloft-versus-surface transport on PM concentrations. Vertical variations of concentrations differed among individual species. The stratification may be important to atmospheric chemistry processes, particularly nighttime nitrate formation aloft, because NO2 appeared to be oxidized by ozone in the stratified aloft layer. Additionally, increases in accumulation-mode particle concentrations in the aloft layer during a fine PM (PM2.5) episode corresponded with increases in aloft nitrate, demonstrating the likelihood of an aloft nighttime nitrate formation mechanism. Evidence of local transport at the surface and regional transport aloft was found; transport processes also varied among the species. The distribution of BC appeared to be regional, and BC was often uniformly mixed vertically. Overall, the combination of time-resolved tower and surface measurements provided important insight into PM stratification, formation, and transport.

Air Pollutants↗
PubMed1994

Concentration of indoor particulate matter as a determinant of respiratory health in children.

The effect of passive exposure to environmental tobacco smoke in the home on respiratory symptoms and pulmonary function level was studied in a cohort of white children aged 7-11 years examined in six US cities in 1983-1988. For 2,994 children with questionnaire-based exposure data, passive exposure to an additional pack of cigarettes smoked daily in the home was associated with increased incidence of lower respiratory symptoms (odds ratio (OR) = 1.25, 95% confidence interval (CI) 1.10-1.42). For 1,237 children with two consecutive 1-week measurements in both winter and summer, a 30-micrograms/m3 increase in the annual average indoor concentration of respirable particulate matter with an aerodynamic diameter of < 2.5 microns (PM2.5)--that is, approximately the effect of one pack per day of smoking--was marginally associated with an increased cumulative incidence of lower respiratory symptoms (OR = 1.13, 95% CI 0.99-1.30). Indoor measurements of PM2.5 showed no direct association with children's pulmonary function measurements. Children whose mothers smoked during pregnancy showed a reduction of -2.6% (95% CI -5.2% to 0.1%) in volume-adjusted forced expiratory flow rates. Therefore, current indoor exposure to PM2.5 increases the cumulative incidence of lower respiratory symptoms, but is only weakly associated with decreased pulmonary function level in preadolescent children.

Air Pollution, Indoor↗
PubMed2005

Application of infrared laser desorption vacuum-UV single-photon ionization mass spectrometry for analysis of organic compounds from particulate matter filter samples.

A new built instrument suitable for laser desorption-single photon ionization time-of-flight mass spectrometry (LD-SPI-TOFMS) with use of Vacuum-UV photons with a wavelength of 118 nm was used for the analysis of organic compounds. Fragmentation-free analysis of a variety of substances was achieved for desorption experiments with pure compounds desorbed from quartz glass filters applying low desorption energies. It was further found that the rate of fragmentation is strongly dependent on the desorption energy. Matrix effects were investigated by desorption experiments utilizing soot spiked with several organic compounds.The characteristics of the desorption process are assessed in more detail and the impact on the analysis of ambient particulate matter (PM) samples on filters are discussed. First results obtained from the application of the technique to the analysis of organic compounds from ambient PM are presented. Furthermore, possibilities of future developments of the method, in particular for analysis of ambient PM, are discussed.

Journal Article↗
PubMed2002

Monitoring atmospheric particulate matter through cavity ring-down spectroscopy.

Cavity ring-down spectroscopy was explored as a means to measure atmospheric optical extinction. Ambient air was sampled through a window on the campus of the University of Florida and transported to a ring-down cell fashioned from standard stainless steel vacuum components. When a copper vapor laser operating at 10 kHz is employed, this arrangement allowed for nearly continuous monitoring of atmospheric extinction at 510 and 578 nm. We have characterized the system performance in terms of detection limit and dynamic range and also monitored a change in atmospheric extinction during a nearby wildfire and fireworks exhibition. The sensitivity and compatibility with automation of the technique renders it useful as a laboratory-based measurement of airborne particulate matter.

Air Pollution↗
PubMed2001

Cardiovascular and systemic responses to inhaled pollutants in rodents: effects of ozone and particulate matter.

Striking similarities have been observed in a number of extrapulmonary responses of rodents to seemingly disparate ambient pollutants. These responses are often characterized by primary decreases in important indices of cardiac and thermoregulatory function, along with secondary decreases in associated parameters. For example, when rats are exposed to typical experimental concentrations of ozone (O(3), they demonstrate robust and consistent decreases in heart rate (HR) ranging from 50 to 100 beats per minute, whereas core temperature (T(co) often falls 1.5-2.5 degrees C. Other related indices, such as metabolism, minute ventilation, blood pressure, and cardiac output, appear to exhibit similar deficits. The magnitudes of the observed decreases may be modulated by changes in experimental conditions and appear to vary inversely with both ambient temperature and body mass. More recent studies in which both healthy and compromised rats were exposed to either particulate matter or its specific components yielded similar results. The agents studied included representative examples of ambient, combustion, and natural source particles, along with individual or combined exposures to their primary metallic constituents. In addition to the substantial decreases in HR and T(co), similar to those seen with the O(3)-exposed rats, these animals also displayed numerous adverse changes in electrocardiographic waveforms and cardiac rhythm, frequently resulting in fatal outcomes. Although there is only limited experimental evidence that addresses the underlying mechanisms of these responses, there is some indication that they may be related to stimulation of pulmonary irritant receptors and that they may be at least partially mediated via the parasympathetic nervous system.

Air Pollutants↗
PubMed2003

World Trade Center fine particulate matter--chemistry and toxic respiratory effects: an overview.

The 11 September 2001 terrorist attack on New York City's World Trade Center (WTC) caused an unprecedented environmental emergency. The collapse of the towers sent a tremendous cloud of crushed building materials and other pollutants into the air of lower Manhattan. In response to the calamity, federal, state, and city environmental authorities and research institutes devoted enormous resources to evaluate the impact of WTC-derived air pollution on public health. Unfortunately, on the day of the disaster, no air-sampling monitors were operating close to the WTC site to characterize and quantify pollutants in the dust cloud. However, analysis of fallen dust samples collected 5 and 6 days after the attack showed that 1-4% by weight consisted of particles small enough to be respirable (Lioy et al. 2002). These particles included fine particulate matter, or PM(subscript)2.5(/subscript) [PM < 2.5 micro m mass median aerodynamic diameter (MMAD)], which can be inhaled deep into the lung and is associated with cardiovascular and respiratory health effects. Because of the extremely high concentrations of dust immediately after the collapse of the towers, even a relatively small proportion of PM(subscript)2.5(/subscript) in the dust clouds could have contributed to breathing problems in rescue workers and others who were not wearing protective masks.

Air Pollutants↗
PubMed2000

Effect of leaded and unleaded gasoline on the mutagenicity of vehicle exhaust particulate matter.

With the removal of lead from gasoline and the use of new technologies, there have been some changes in vehicle emissions. In order to find out if the unleaded gasoline has the ability to reduce the emission of pollutants, leaded and unleaded gasoline were tested on a Santana engine dynamometer under a standard test cycle. The concentrations of hydrocarbons (HC) and carbon monoxide (CO) in emission were analyzed. The extracts of total exhaust particles were also collected and the components were detected by gas chromatography/mass spectrometry (GC/MS). A series of different end point genotoxicity tests, including the Ames test, the single cell gel electrophoresis (SCGE) assay, and micronucleus induction assay, were performed to investigate the mutagenicity in the two kinds of gasoline. We found that unleaded gasoline could reduce the emission of CO and HC and significantly decrease the quantity of vehicle exhaust particulate matter by 60%. As for the component analysis, only 23 kinds of organic substances adsorbed onto the particles were identified in the unleaded gasoline, while 32 kinds of compounds were detected in the leaded gasoline. The genotoxicity tests indicated that both types of gasoline could enhance the number of histidine-independent colonies in the Ames test, cause DNA damage, and increase the frequency of induced micronucleus in the Chinese hamster lung (CHL) cells. For the same particle weight, no difference was found between their mutagenicity. Because of the decrease in the emission of CO, HC, and particles in unleaded gasoline, this gasoline has some benefits for the environment and human health.

Animals↗
PubMed2003

Analysis of nitrated polycyclic aromatic hydrocarbons by liquid chromatography with fluorescence and mass spectrometry detection: air particulate matter, soot, and reaction product studies.

Polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH) are environmental pollutants which pose a threat to human health even at low concentration levels. In this study, efficient analytical methods for the analysis of nitro-PAH and PAH (extraction, clean-up, chromatographic separation, and spectrometric detection) have been developed, characterized, and applied to aerosol samples. The separation and quantification of 12 nitro-PAH was carried out by reversed-phase high performance liquid chromatography (HPLC), on-line reduction, and fluorescence detection. The detection limits were in the range of 0.03-0.5 microg L(-1) (6-100 pg in the investigated sample aliquots), and the recovery rates from soot samples were 70-90%. Nitro-PAH and PAH concentrations have been determined for different types of soot and for urban, rural, and alpine fine air particulate matter (PM2.5). For the first time, trace amounts of nitro-PAH have been detected in a high-alpine clean air environment. The on-line reduction and fluorescence technique has been complemented by atmospheric pressure chemical ionization time-of-flight mass spectrometry (APCI-TOF-MS). The MS detection allowed the analysis of partially nitrated and oxygenated PAH in laboratory studies of the heterogeneous reaction of PAH on soot and glass fiber substrates with gaseous nitrogen oxides and ozone. It led to the tentative identification of a previously unknown nitrated derivative of the particularly toxic PAH benzo[ a]pyrene (BaP-nitroquinone), and provides the first experimental evidence that PAH-nitroquinones can be formed by reaction of PAH with atmospheric photooxidants.

Journal Article↗
PubMedDate not supplied

Particulate matter and manganese exposures in Indianapolis, Indiana.

The distribution of PM(2.5) and manganese (Mn) personal exposures was determined over a 4-month period in Indianapolis, IN, at a time when the gasoline additive, methylcyclopentadienyl manganese tricarbonyl (MMT), was not being used. The data collection period coincided with the data collection period in the Toronto, ON, study, where MMT had been used as a gasoline additive for over 20 years. The inferential or target population consisted of noninstitutionalized residents of the Indianapolis area during the monitoring period (from May 1996 through August 1996) who were at least 16 years old. The survey instruments used in this study (and also in Toronto) included a household screener form (HSF), a study questionnaire (SQ), and a time and activity questionnaire (TAQ). The SQ was administered to elicit information about the participant and his/her activities, occupation, and surroundings that might be relevant to his/her exposure to particles and Mn. In addition to the personal particulate matter (PM) and elemental 3-day monitoring, 240 participants completed a TAQ on a daily basis during the actual monitoring period. Also, a subset of participants had 3-day outdoor and indoor stationary monitoring at their home (approximately 58 observations), and sampling was conducted at a fixed site (approximately thirty-three 3-day observations). The quality of data was assessed and compared to the Toronto study in terms of linearity of measurement, instrument and method sensitivity, measurement biases, and measurement reproducibility. Twenty-six of the sample filters were subjected to two analyses to characterize the within-laboratory component of precision in terms of relative standard deviations (RSDs). The median RSD for Mn was 8.7%, as compared to 2.2% for Toronto. The quality assurance (QA) laboratory exhibited a clear positive bias relative to the primary laboratory for Al and Ca, but no systematic difference was evident for Mn. A high interlaboratory correlation (>0.99) was also attained for Mn. Mean field blank results for PM and Mn were 0.87 microg/m(3) and 0.71 ng/m(3), respectively, which were comparable to the Toronto study. The median RSDs for colocated fixed site and residential samples ranged from 2.2% to 9.0% for PM and from 8.8% to 15.3% for Mn, which were close to those observed in Toronto. For the PM(10), the 90th percentile indoors was 124 microg/m(3) compared with 54 microg/m(3) outdoors. This pattern was even more pronounced for the PM(2.5) data (90th percentiles of 92 microg/m(3) indoors vs 30 microg/m(3) outdoors). Personal PM(2.5) was somewhat higher than the indoor levels, but the percentiles seemed to follow the more highly skewed pattern of the indoor distribution. This difference was largely due to the presence of some smokers in the sample; e.g., exclusion of smokers led to a personal exposure distribution that was more similar to the outdoor distribution. The estimated 90th percentile for the nonsmokers' personal exposures to PM was 43 microg/m(3) compared with 84 microg/m(3) for the overall population. In general, the Indianapolis PM levels of a given type and cut size were somewhat higher than the levels observed in Toronto, e.g., the median and 90th percentile for the personal PM(2.5) exposures were 23 and 85 microg/m(3), respectively, in Indianapolis, while in Toronto, the corresponding percentiles were 19 and 63 microg/m(3). The cities' distributions of the proportion of the PM(10) mass in the 2.5-microm fraction appeared similar for the residential outdoor data (medians of 0.67 and 0.65 for Indianapolis and Toronto, respectively, and 90th percentiles of 0.83 for both cities). For the indoor data, Indianapolis tended to have a larger portion of the mass in the fine fraction (median of 0.80 compared to 0.70 for Toronto). Unlike the PM, the Indianapolis indoor Mn concentration levels were substantially lower than the outdoor levels for both PM sizes, and the median personal levels for Mn in PM(2.5) appeared to fall between the median indoor and outdoor levels. The personal Mn exposure distributions exhibited more skewness than the indoor or outdoor distributions (e.g., the means for the personal, indoor, and outdoor distributions were 7.5, 2.6, and 3.5 ng/m(3), respectively, while the medians were 2.8, 2.2, and 3.2 ng/m(3), respectively). At least a substantial portion of the high end of the personal exposure distribution appeared to be associated with occupational exposures to Mn. In general, the Mn levels in both cut sizes in Indianapolis were approximately 5 ng/m(3) smaller than those in Toronto (e.g., the estimated median and mean levels for personal Mn exposures in PM(2.5) were 2.8 and 7.5 ng/m(3), respectively, in Indianapolis, but were 8.0 and 13.1 ng/m(3) in Toronto). For the nonoccupational subgroups with no exposure to smoking and no subway riders in the two cities, the medians (2.6 ng/m(3) in Indianapolis and 7.8 ng/m(3) in Toronto) were similar to those for the overall populations, but the means were substantially smaller (3.1 ng/m(3) in Indianapolis and 9.2 ng/m(3) in Toronto). The median proportion of Mn in the fine fraction (relative to the PM(10) Mn) for Indianapolis was 0.39 for outdoors and 0.55 for indoors; these ratios were somewhat smaller than the corresponding Toronto medians (0.52 and 0.73). The study found high correlations for particulates and Mn between personal exposures and indoor concentrations, and between outdoor and fixed site concentrations, and low correlations of personal and indoor levels with outdoor and fixed site levels. The pattern was similar to that observed for Toronto, but slightly more pronounced. The PM(10) Mn concentrations (log scale) generally exhibited stronger associations among these various measures than the PM(2.5) Mn concentrations. Comparisons of the particulate distributions between PTEAM (Riverside, CA) and the Indianapolis and Toronto studies were also made.

Adolescent↗
PubMed2006

Saving energy and reducing emissions of both polycyclic aromatic hydrocarbons and particulate matter by adding bio-solution to emulsified diesel.

Development of emulsified diesel has been driven by the need to reduce emissions from diesel engines and to save energy. Emulsification technology and bio-solution (NOE-7F) were used to produce emulsified diesel in this study. The experimental results indicated that there were no significant separation layers in W13 (13 wt % water + 87 wt % PDF), W16 (16 wt % water + 84 wt % PDF), W19 (19 wt % water + 81 wt % PDF), E13 (13 wt % NOE-7F water + 87 wt % PDF), E16 (16 wt % NOE-7F water + 83 wt % PDF), and E19 (19 wt % NOE-7F water + 81 wt % PDF) after premium diesel fuel (PDF) was emulsified for more than 30 days. In addition, there was no significant increase in damage from using these six emulsified fuels after the operation of the diesel generator for more than one year. The energy saving and reduction of particulate matter (PM) and total polycyclic aromatic hydrocarbons (PAHs) for W13, W16, W19, E13, E16 and E19, respectively, were 3.90%, 30.9%, 27.6%; 3.38%, 37.0%, 34.9%; 2.17%, 22.2%, 15.4%; 5.87%, 38.6%, 49.3%; 5.88%, 57.8%, 58.0%; and 4.75%, 31.1%, 47.3%, compared with PDF. The above results revealed that the bio-solution (NOE-7F) had a catalytic effect which elevated the combustion efficiency and decreased pollutant emissions during the combustion process. Furthermore, bio-solution (NOE-7F) can stabilize the emulsified fuels and enhance energy saving. Thus, emulsified fuels are highly suitable for use as alternative fuels. Due to the increasing price of diesel, emulsified diesel containing NOE-7F has potential for commercial application.

Emulsions↗
PubMed2005

Effects of ambient particulate matter on peak expiratory flow rates and respiratory symptoms of asthmatics during Asian dust periods in Korea.

OBJECTIVE: Dust generating events frequently produce ambient dust particles that are less than 10 microm in diameter, and these have been linked to adverse effects in the general population. However, the evidence linking these particles to adverse effects on the airways of asthmatic individuals is limited. The objective of this study was to investigate the possible adverse effects of Asian dust events on the respiratory functions and symptoms of subjects with bronchial asthma. METHODOLOGY: From March to June 2002, individuals were enrolled who had been diagnosed as having asthma by bronchial challenge or by their bronchodilator response. The patients were divided into three groups according to asthma severity: mild, moderate and severe. Patients with other major disease states were excluded. Patients completed twice-daily diaries monitoring PEF, respiratory symptoms, and daily activities. The daily and hourly mean levels of particulate matter <10 microm in diameter (PM(10)), as well as nitrogen dioxide (NO(2)), sulphur dioxide (SO(2)), ozone (O(3)) and carbon monoxide (CO) were measured at 10 monitoring sites in Incheon, Korea. RESULTS: Dust events occurred 14 times during the study period. On dusty days there were increased levels of PM(10), decreased levels of NO(2) and SO(2), and no change in the CO levels, compared to the levels on control days. An increase in PM(10) concentration was associated with increases in PEF variability of >20% (P<0.05), more night-time symptoms (P<0.05), and a decrease in the mean PEF (P<0.05), calculated by longitudinal data analysis. In contrast, there was no association between the PM(10) levels and bronchodilator inhaler use or daytime respiratory symptoms. Using a general additive Poisson regression model, a borderline association was noted between PM(10) and respiratory symptoms, with a relative risk of 1.05 (95% confidence interval (CI), 0.99--1.17). There was no association between the PM(10) concentrations and PEF measurements, with PEF variability of >20% between the morning and evening values and a relative risk of 1.05 (95% CI, 0.89--1.24) in all subjects. CONCLUSIONS: This study provides evidence that Asian dust events are impacting on the respiratory symptoms of subjects with bronchial asthma, and ambient air pollution, particularly elevated PM(10), might be one of the aggravating factors.

Adult↗